1. Field of the Invention
The present invention relates to a method for controlling equipment in a semiconductor fabrication system and, more particularly, to a method through which discordance between the actual state and stored state of equipment components can be prevented using a unit state change monitoring module included in a host computer. Thereby, the overall efficiency in controlling productivity of the equipment can be considerably enhanced.
2. Description of the Related Art
Generally, the fabrication of semiconductor devices involves highly precise processes that require finely tuned precision equipment. Several pieces of precision equipment are typically employed in sequence and arranged on a semiconductor processing line. The operation of each piece of precision equipment on the line is closely monitored by operators to maintain and enhance the efficiency of the processing line.
As shown in FIG. 1, conventional fabrication equipment 3 are disposed on a conventional processing line. When a lot 10 of workpieces, such as wafers, are introduced into the equipment 3, the equipment 3 performs a fabrication process on the lot 10. The equipment 3 is connected on-line to a host computer 1 through an equipment server (not shown). An operator interface (O/I) 2, for example an operator interface personal computer (O/I PC), is also connected on-line to the host computer 1. Through the O/I 2, an operator informs the host computer 1 that a process using the equipment 3 is about to commence. The host computer 1 immediately downloads preset process settings to the equipment. Process settings may include, for example, a desired process time duration or a desired process temperature. Then the process equipment 3 performs on the workpieces of each lot 10 based on the process settings received.
After the host computer 1 downloads the preset process settings, the equipment 3 operates its one or more subsidiary units or components, for example, loading and unloading ports (not shown) and chambers 4, to perform the process according to the downloaded process settings.
In such a conventional semiconductor fabrication equipment controlling system, when a first unit (e.g., chamber 4a) is in one state (e.g., DOWN), and another unit (e.g., chamber 4b) is in a different state (e.g., UP or RUN), the first unit may need to be changed from the one state to the different state. In such a case the operator must operate directly on the console (not shown) of the equipment 3 to change the state of the first unit. In a separate step, the operator must store the new state of the first unit in the host computer 1 through the O/I 2. Thereafter, the host computer 1 continuously stores in its data base the states of the respective units of the equipment 3 entered by the operator.
However, such a conventional controlling system suffers from several problems. First, the states of the equipment are frequently changed and the host computer of the conventional controlling system cannot automatically recognize the changes in real time. This may result in discordance between equipment state data stored in the data base of the host computer and the actual states of the equipment.
Secondly, due to this discordance, the host computer cannot produce accurate results for controlling the processing line if those results depend on the states of the units of the equipment 3. As a result, it is impossible to properly control the equipment as soon as a unit state is changed by the operator.
Thirdly, the operator using the discordant data from the host computer to calculate the operating rate of the equipment obtains an incorrect rate which may cause the operator to select the wrong operating rate for the following process. This may result in inaccurate control of the whole process line and reduced productivity of the line.
Finally, the states of the equipment units can be changed only by the operator moving to the equipment and operating directly on its console. If the console is positioned away from the O/I 2, such changes may result in reduced efficiency in controlling the equipment.